Hang in there hope! You have to focus on you. Make yourself better and happy without your S. It's hard...it's super hard. 4 years ago, my W filed for divorce, was dating someone else, and I was living in an apartment. I even started dating (which in hindsight was a mistake). Literally 5 days before the divorce was to be final, she called it off and we began the reconciliation process.
You really have to focus on you and heal from the relationship. We never properly healed and there are a number of wounds from dating others...even 4 years later. I'm back in the stormy seas of limbo, but am DBing again and see results. I'll tell you, it's daily work, reading, and posting here. I can completely wrap my head around detaching, and even feel detached for periods of time, then I struggle again. Practice your 180s on others as well as your S.
Hang in there and begin the process of you! It takes the pain away and you'll be better off for it no matter where the relationship end up!
Me: 44 Her: 42 T: 22, M: 20 D:18, S:16, S:11 Sep: 6 months in 2002 Sep again: March 15, 2015 (5 months) WAW talk again: January 21, 2019